
\begin{table}[htbp!]
\centering
\caption{\textbf{Natural experimental studies of ballot position effects from \cite{blom2016ballot} and others, with  information added on campaign spending} \label{tab:exp_evidence}}
\scalebox{0.7}{
\begin{threeparttable}
\begin{tabular}{p{50mm}lH>{\centering}m{45mm}p{70mm}}
\toprule
Natural experimental studies & Identified ballot position effect & Election date & Campaign spending allowed? & Election \\
\hline
& \\ 
\multicolumn{4}{l}{\textit{Natural experiments from the USA (random rotation of order of candidates)}} & \\ \\ 
\cite{alvarez2006much} & Positive effect of being listed first & November 3 & Allowed & California, 1998 All statewide races \\
\cite{chen2014impact} & Positive effect of being listed first & November 2-7 & Allowed & North Dakota, 2000-2006 All statewide elections  \\
\cite{darcy1986position} & No position effect & September 12-15 \& \ October 23 & Allowed & Colorado, 1984 All statewide races \\
\cite{ho2006} & Positive effect of being listed first & October 7 & Allowed & California, 2003 Gubernatorial recall election \\
\cite{ho2008estimating} & Positive effect of being listed first & November 3-8 & Allowed* & California, 1978-2002 All statewide races  \\
\cite{koppell2004effects} & Positive effect of being listed first & November 3 & Allowed & New York City, 1998 All statewide Democratic primaries  \\
\cite{krosnick2004unrecognized} & Positive effect of being listed first & November 3, 1982 \& November 7, 2000 & Allowed & Ohio (All statewide races), North Dakota(All statewide races) and Californa(President and Senate), 2000  \\
\cite{meredith2013causes} & Positive effect of being listed first & March \& November (1995-2008) & - & City council \& California, 1995-2008 City council and school board elections \\
\cite{miller1998impact} & Positive effect of being listed first & November 3 & Allowed & Ohio, 1992 All statewide and countywide races \\
\cite{pasek2014} & Positive effect of being listed first & & Allowed & California, All statewide general election, 1976-2006 (where name order was rotated) \\
& \\
\multicolumn{4}{l}{\textit{Natural experiments from outside the USA}} & \\ \\
\cite{faas2006importance}:  & Positive effect of being listed first & September 21 & Regulated spending: Broadcast through TV/Radio granted during a period before the election & Bavarian state elections in Germany  \\
\cite{geys2003ballot}:   & Positive effect of being listed first & May 21 & Strictly regulated spending  & Regional elections in Brussels  \\
\cite{king2009ballot}: & Positive effect of being listed first & Election date & Allowed & Australian federal elections  \\
\cite{blom2016ballot}:  & Positive effect of being listed first & November 19 & Allowed & Danish local/regional elections  \\
\bottomrule
\end{tabular}
* California employs a randomization-rotation scheme, where the order is randomized in the first assembly district and rotated for all subsequent 80 assembly districts. In this context it less likely that parties can respond to ballot order effects.
\end{threeparttable}}
\end{table}

